| 摘要 |
A sound decoder (10) has a decoding unit (11) and an amplification control unit (12). The decoding unit (11) decodes a received coded sound signal (bit stream) BS and outputs a decoded sound signal SP. The amplification control unit (12) monitors occurrence of a frame error in the coded sound signal BS. When continuous frame errors more than a predetermined reference number of frame errors take place,the amplification control unit (12) outputs an amplification instruction after the continuous frame errors are absent for a time corresponding to a predetermined number of frames. As a result, in place of a codebook data DCB generated by the decoding by the decoding unit (11), amplified codebook data DACB generated by amplifying the codebook data DCB is fed to a synthesizing filter unit (17) and written as new original codebook data DCBO in a codebook decoder (18) of the decoding unit (11). Therefore, after continuous frame errors, a coded sound signal BS normally inputted can be decoded with an electric power which is nearly equal to the primarily needed electric power, and the subjective sound quality is improved. <IMAGE> |
